The Galileo mission to Jupiter exceeded the most optimistic predictions.
Data allowed new insights into our solar system's formation and evolution and the origins of life.
Galileo is the first craft to enter a planet's atmosphere and send back data.
Jupiter was found to be much hotter and windier than thought, with an atmospheric chemical composition closely resembling the sun's.
Jupiter's surface energy comes from heat escaping from deep in the planet.
Jupiter's rings, formed by cosmic debris smashing into moons, are more numerous and complex than thought.
Jupiter was probably formed under cooler conditions.
Jupiter's moons Europa and Callisto probably contain subsurface salty oceans.
Europa may support life forms.
Jupiter's gravity changes Europa's shape as it orbits.
Europa's core is metallic, surrounded by rock, water, and ice.
Its magnetic north pole reverses.
Io has a giant iron core overlain by rock and over 100 active volcanoes.
Ganymede has its own magnetic field, indicating a fluid metal core.
Galileo was launched aboard space shuttle Atlantis in October 1989 and took six years to reach Jupiter.
A probe was released from Galileo in July 1996, entering Jupiter's atmosphere December 7th and sending back data for 30 minutes.
After two years studying Jupiter and its four largest moons, in 1998 Galileo's orbit was rerigged to focus on Europa for two more years.
Galileo's main antenna failed to unfurl.
In 1999 Galileo began experiencing instrument damage from Jupiter's intense radiation.
By 2000 fuel was low and officials debated the cost-effectiveness of further operations.
